Magnetic induction surrounding house, is it possible?

Hey guys, I was contemplating the idea of Wireless Energy after reading the Dell article.

Would it be possible to surround your entire house in a magnetic induction field, then have battery shaped adapters that put out their respective voltages? This idea also is collaborated partly with Fringe, how the scientist engulfed the city with perception altering electromagnetic waves.

Of course, this won't be efficient at all, but it's a start to wireless energy, would it work?

Problem is, the strength of the magnetic field had to be so strong that all iron objects in the house would fly wild around. A dangerous place to be. Apart from that - it should be theoretical possible, but extremly ineffective.

Your house is already completely surrounded by a magnetic field that varies between 30 - 60 µT.

VNE, you lost me.

If I were to hold a steel object to my sonicare charger stand, would it stick to it?

Hey, there are a whole bunch of crazies around here that swear that just living near an AC power line has all kinds of adverse health consequences (i.e. it makes them stupid). Now you want to make it worse?

(well that explains why they're complaining)

No it wouldn't, but it would heat up to some degree, the field it puts out is AC, the north and south magnetic fields form and change polarity on the order of a few thousand times per second, the net magnetic force is 0.
Expand something like that the to area of a house and if you can't find a problem with it, trust me, it will find a problem with you, or with something in the house. While optimal power is drawn by objects (tuned inductors) that meet the proper frequency requirements that does NOT mean that other objects can't also draw power from the field, given any specific frequnecy there will always be a specific physical metalic object size nearby that will be harmonic to it, and draw power, and re-emit it, or just heat up.

Grossel said:

Problem is, the strength of the magnetic field had to be so strong that all iron objects in the house would fly wild around. A dangerous place to be. Apart from that - it should be theoretical possible, but extremly ineffective.

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No, it'd be like living in a microwave oven on LOW all the time.

Transmitting power without tightly coupled (touching, or very nearly so) coils involves radiating energy out. This means that the efficiency is extremely low and also that the whole area must be exposed to extremely high levels of RF power. Any field powerful enough that a small coil could couple 1W off it is far too intense for humans, even by industrial exposure standards. And that's because at that point it'll cause immediate, observable problems, even "cooking" a person. Considering the state of affairs where we blame cell phones and power lines for causing cancer, I don't see where people would accept an antenna in the living room that radiated something millions of times more intense so they could avoid plugging in a cord.

The technology has uses for UAVs and broadcasting power from an orbiting solar platform and all sort of potential uses. But an unaimed, distant, occupied, consumer-occupied setting, it's a hoax. The technology can't do it. We can't make an EM antenna that knows to avoid people and pets in the room. OK, technically, you could have a highly directional antenna that tracked a single appliance and turns to direct a beam at it. But RF can't be foucsed into a laser beam, and even if it could, it's still too intense when there's a risk of someone getting in the way of it.

iflymyhelishigh said:

VNE, you lost me.

If I were to hold a steel object to my sonicare charger stand, would it stick to it?

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I don't know about your Sonicare™ stand but what I was referring to was the Earth's magnetic field which has a field strength at the surface of anywhere between 30 - 60 µT depending on your latitude. It was an attempt at humor but obviously failed. Sorry.

Not really a microwave oven Oznog, the frequencies that are of interest are much lower. Only a few hundred KHZ at most I think, and much higher power than has ever been studied for any length of time, so we have no idea what it'd be like.

He was also talking about magnetic induction coupling, not EM emissions.

So how is this different from the people in the neighborhoods located right next door to the high powered 100's of KW AM radio station transmitters that are located all over the world?

He's talking about creating a huge pulsating magnetic field around his house then using coils to pull power from it. Much different than transmitting EM radiation and picking it up with an antenna.

smanches, You can't have a pulsating magnetic field without broadcasting EM radiation it's straight up physically impossible. The only difference between these witricity experiments and getting electricity from an RF field is that the coupling is primarily magnetic. Many Am radios use loopstick antennas which rely on magnetic coupling similarly. Considering the power levels required you won't see this becoming mainstream anytime soon, there would have to be long term studies done to find out what the possible interactions are with real world objects, even the few tests that have been done are all in fully shielded rooms and people aren't allowed to be in the room during the tests. I personally think it's a great technology for power supply problems that abound, a universal charging standard that doesn't require plugs would be nice, but we know industry can't get around one standard like that, there will be a dozen or more competing standards all working similarly and intentionally incompatible with each other. The pipe dream of something like this working in large scale areas such as a room are difficult enough let alone something the size of a house.

Sceadwian said:

smanches, You can't have a pulsating magnetic field without broadcasting EM radiation it's straight up physically impossible. The only difference between these witricity experiments and getting electricity from an RF field is that the coupling is primarily magnetic. Many Am radios use loopstick antennas which rely on magnetic coupling similarly. Considering the power levels required you won't see this becoming mainstream anytime soon, there would have to be long term studies done to find out what the possible interactions are with real world objects, even the few tests that have been done are all in fully shielded rooms and people aren't allowed to be in the room during the tests. I personally think it's a great technology for power supply problems that abound, a universal charging standard that doesn't require plugs would be nice, but we know industry can't get around one standard like that, there will be a dozen or more competing standards all working similarly and intentionally incompatible with each other. The pipe dream of something like this working in large scale areas such as a room are difficult enough let alone something the size of a house.

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I understand there will be plenty of EM radiation, but we're using magnetic coupling, not collecting EM radiation. I find it to be distinct enough to make a difference.

smanches, you're forgetting, just because you intend to use magnetic coupling to draw the power off does NOT mean that some isn't radiated. At the power levels required for devices in large areas you're talking about low frequency EM propagation over MASSIVE distances with virtually not physical boundary limits. Now think about the practicalities. Sure you might be able to do it in 1 house with large efficiency penalties, studies need to be done about common materials in these fields though, specifically the human body. Now add that up a few hundred times.. And note that no two sources of this witricity is going to be able to be perfectly in phase with the others so you'll get in harmonic effects that could cause unknown effects. The frequencies typically used for these kinds of energy broadcasts also happens to be in the AM band so you're talking about a nearly universal blackout on lower power AM transmission. Don't forget the possible effects of a device malfunction such as a short to something that acts well as an antenna at those frequencies (say a metal fence)
There are so many unknowns to hail this as the sollution to wireless energy transfer in a home setting is ludicrous =) The media just latches onto this like it's some awesome new invention, which it is NOT, it's been in use for a very long period of time now and it's never proven practical on large scales.

It does have interesting possibilities for room level power levels, especially when that room can be shielded but interactions with the human body could be complex. Low frequency high power/energy oscillating magnetic fields will interact at least on some extent with the human brain, at the very least it could possible cause mild disturbances in behavior or mental acuity. There's absolutely no way to know until it's thoroughly tested and explored for specific uses.

Considering that pacemakers (and other cardiac implants) can be upset even by airport metal detectors, wi-power would seem very risky to me.

Or, implement wi-power and within a few years the pacemakers will be eliminated as each patient is killed off.

Or for the trouble makers implant them with pace makers that are Wi -power based! They get to far from the base and their short term battery goes dead they run out of juice! Literally.

tcmtech said:

So how is this different from the people in the neighborhoods located right next door to the high powered 100's of KW AM radio station transmitters that are located all over the world?

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Simple- even "next door"- which is likely a thousand feet or more- the amplitude is reduced far below what would be useful for powering devices. If you were within a few feet of a 100KW transmitter, a small coil- under a foot- could potentially capture a few watts of power to drive a device. But that level of RF energy is dangerous to humans, nevermind that it would interfere with most electronic devices anyways.

The frequency does not change the basic problems: any amplitude capable of delivering actual useful "power" is far too intense for human or electronics, and no frequency- even if the receiver is "tuned"- only delivers to the target device. That sort of link is fiction. Omnidirectional broadcasts without close coupling both radiate wasted power in all directions and the loading on the antenna won't change when the target device is on or off.

there's some company who's name escapes me, that is experimenting with stuff like this. the problem is, is that their electromagnetic inductors are the size of your house. (well that all depends on the size of the house) the coils are about 60 feet in diameter, and take a couple of thousand volts to operate.